This project will evaluate general patterns of population average and individual variation in change across distinct personality and well-being constructs in major longitudinal studies on aging. The lALSA/HALCyon network of over 40 longitudinal studies permits a strong and unified program of research designed to understand the mechanisms driving intraindividual changes in personality. The international set of longitudinal studies also permits tests ofthe cross-cultural generalizability ofthe mechanisms explaining personality change and stability. We will model change In personality traits and well-being dimensions, with age as the temporal metric, and examine their association to one another. We will also examine models for process-based change as well as correlated and coupled change In personality variables. Additionally, we will use the aforementioned change parameters for personality, well-being and risk-factor dimensions (Intercepts, slopes) to predict important outcomes, especially health, disease and cognitive outcomes In later life. Does change In personality predict important health and cognitive endpoints (e.g., cardiac events, onset of dementia, mortality)? Finally, we will model change in personality trait and well-being dimensions using alternative temporal metrics, such as distance to death, and to normative life or health events such as initiation of caregiving, death of spouse or diagnosis of chronic disease. RELEVANCE (See instructions): Most major studies of aging contain personality measures, but rarely have analyses been coordinated across multiple studies. The proposed work will leverage a large number of longitudinal studies to provide the clearest picture of personality stability and change, and how it relates to aging-related changes In cognition and health outcomes.